The main long-term objectives of this research project encompass the biochemical and physiological parameters of two macromolecular cell surface components, the poly(gamma-D-glutamyl) capsule of Bacillus licheniformis and polymers containing sialic acid in Escherichia coli. Much of the effort of the past few years has been concerned with the structure and biosynthesis of these cell envelope polymers. On the basis of work already accomplished (determination of the structure of these poly(gamma-D-glutamyl) capsule; biosynthetic studies on the membranous polyglutamyl synthetase and sialyltransferase complex; isolation, characterization and role of undecaprenyl phosphate in sialyl polymer synthesis), these objectives are a logical continuation of studies currently in progress and include elucidation of the precise molecular events whereby membranous enzyme interactions participate in the synthesis of cell surface components. In sialyl polymer synthesis, major emphasis will focus upon: 1) the mechanism of assembly of the sialtransferase complex; 2) a detailed study of the mechanism of polymerization; and 3) further structural studies on the nature of the biosynthetic and in vivo polymers. Similarly, future studies on the biosynthesis of the poly(gamma-D-glutamyl) polymers will be directed at understanding the mechanism of activation, racemization and polymerization of this unique capsular polymer. These studies will involve a detailed analysis of: a) the nature of the activated glutamyl intermediates; b) deterination of the direction of polymer growth; c) structural studies on the nature of an endogenous, high molecular weight "acceptor" of activated glutamyl moieties; and d) the possible involvement of the capsule in bacteriophage infection. These studies are directed towards elucidating the relationship of these cell envelope components to other surface structures and should contribute significantly to our understanding of several dynamic and functional parameters of the cell periphery perhaps associated with pathogenicity.